Method for adhesive bonding of aluminum

Abstract

A method is disclosed for laminating plastics resin films to aluminum. The aluminum surface to be bonded is treated with a coating composition consisting essentially of an aqueous solution of polyacrylic acid or esters thereof and at least one acid selected from the group consisting of H 2 ZrF 6 , H 2 TiF 6 and H 2 SiF 6 . After this coating has dried, the plastics resin film is bonded to the aluminum, using dry laminating adhesives.

I claim: 
     
       1. In a method for bonding a plastics resin film to aluminum comprising applying an adhesive to said film or said aluminum, drying said adhesive, contacting said film and said aluminum with said adhesive therebetween to form a laminate and subjecting said laminate to heat and pressure to bond said laminate the improvement comprising treating the surface of said aluminum to be bonded with a composition consisting essentially of an aqueous solution having from about 0.5 to about 10 grams per liter of polyacrylic acid or esters thereof and from about 0.2 to about 8 grams per liter of at least one acid selected from the group consisting of H 2  ZrF 6 , H 2  TiF 6  and Hp 2  SiF 6  and drying said composition on said aluminum prior to contacting said film and said aluminum with said adhesive therebetween. 
     
     
       2. The method of claim 1 wherein said polyacrylic acid esters comprise methy, ethyl and butyl esters. 
     
     
       3. The method of claim 1 wherein said plastics resin film comprises polyesters, polyethylenes and polypropylenes. 
     
     
       4. The method of claim 1 wherein said adhesive comprises one part polyurethanes, two part polyurethanes, polyethers, polyesters, two component epoxy-modified polyesters or polyurethanes, acrylics and acrylic copolymers, vinylidene chloride copolymers, and epoxies.